A. Field of the Invention
The invention concerns a device for fine positioning of a component, especially for vertical fine positioning of an objective or a revolving objective nosepiece in microscopy, with a lever system and a drive for the lever system.
The device being discussed here is, very generally, a device for fine positioning of a component. This component can be, for example, a fine-focusing stage for microscopes. Here, in particular, it is a device for vertical fine positioning of an objective or a revolving objective nosepiece, but the teaching claimed here is not limited to that specific application.
B. Description of the Prior Art
A galvanometer lifting table is already known in practice, but that has a tilting rather than a parallel lifting movement. Such a galvanometer lifting table is in any case not suitable for positioning if a parallel lift is required without a tilt error.
A fine focusing stage is known from German Patent 196 50 392 A1. In that patent, the component to be raised or lowered is designed as an object plate. Because of stiffness, the known fine focusing stage is not suitable for fine positioning of an objective or a revolving objective nosepiece. In addition to that, the known fine focusing stage is extremely limited with respect to its maximum travel.
If one wishes to finely position an objective or a revolving objective nosepiece of a microscope, parallel lifting movement is absolutely necessary because of the optical requirements. This lifting movement must be obtained with extremely accurate relative axial positioning, which should be better than 20 nm. Such accuracy is not attainable in any case for ordinary drive designs.
In many applications in microscopy, work is done directly on the object being examined. For instance, work can be done on the object by externally mounted micromanipulators during observation. Focusing of the object stage would be accompanied by undesirable relative movement between the object and the micromanipulators, and that would substantially increase the cost of the equipment. Thus it is desirable, in such applications, for the focusing to be accomplished on the objective or revolving objective nosepiece with the object stage stationary. That must be accomplished with a device of the type stated initially, with the lifting means having the desired accuracy with respect to the axial relative positioning.